I would like to hire an Open Cart Developer

We have several issues with our opencart shopping mall. I wonder if you can fix these errors. Please see the followings and contact me. Thanks in advance. Issue 1) One same order ID used for multi orders A customer has made two orders and the order number of the first order has been used again for the second order. The first order was paid by PayPal with the amount of $ 472.39 on 19 May and the product was shipped. The first order was done without any issue. The 2nd order was placed on May 28th. The customer used [login to view URL] for the payment ($ 529.62) but Opencart system did not generate a new order number for the second order and used the old number of the day of May 19. We treated the order with old order number was completed already and did not ship a product to the customer and it cause customer's complainant. Issuese 2) Status display error PayPal report shows that the payment was paid already but Opencart status says as Pending instead of processing. When payments are paid, status must be processing. Issue 3) missing order Some order are paid via PayPal but these order are going to under missing order. We did not note the order and failed to ship products. How can we prevent any missing order? Issure 4) refund error Unable to submit refund at paypal admin tool. error message "Refund order data not found"